1. Field of the Invention
The present invention relates to antidiabetic composition comprising 7-thiaprostaglandin E.sub.1 or its derivative as the active ingredient.
2. Description of the Prior Art
Prostaglandins have various physiological activities such as potent platelet aggregation inhibitory activity, vasodilating activity, hypotensive activity, gastric juice secretion inhibitory activity, smooth muscle contracting activity and diuretic activity and are substances which are useful for curing or preventing peripheral circulation disorders, myocardinal infarction, angina pectoris, arteriosclerosis, hypertension, gastric ulcer, duodenal ulcer, etc.
Of these prostaglandins, prostaglandins E.sub.1 have recently attracted attention in respect of effects to improve peripheral circulation through their platelet aggregation inhibitory activity and vasodilating activity. Such compounds are clinically found useful for curing various diseases including Buerger's disease, arteriosclerosis obliterans and like arteriostenosis, ischemic ulcer and diabetic gangrene. Of these diseases, diabetic gangrene, which is one of the complications of diabetes, is though to be induced by the participation of factors associated with peripheral arteriosclerosis, diabetic microangiopathy, diabetric neuropathy, opportunistic infections and the like. Reports are made as to the efficacy of prostaglandins E.sub.1 on diabetic gangrene (see Haruhiko Ninomiya et al., "Modern Medical Care," 15, 710-712, 1983; Ryuji Sano et al., "Modern Medical Care," 13, 142-148, 1981; Yasuhiro Oribe et al., "Diabetes," 24(8), 853-860, 1981; Haruhiko Nishima et al., "Prostaglandins--Advances in Clinical applications II," Gendai Iryosha, 228-231, 1985; Hiroyuki Hososhima et al., the same publication, 232-235, 1985; Nobuyuki Asakawa et al., the same publication, 236-241, 1985; Haruhito Nomoto et al., the same publication, 242-244, 1985; Hiroshi Hayashi et al., "Prostaglandins--Advances in Clinical applications," Gendai Iryosha, 165-173, 1983; and literature citing these reports). Effective cases of prostaglandins E.sub.1 for diabetic neuropathy have also been recently reported (see Tsuguo Ebihara et al., "Prostaglandins Advances in Clinical Applications II," Gendai Iryosha, 245-248, 1985; Kenshin Kishida et al., the same publication, 249-256, 1985; Fumio Umeda et al., the same publication, 257-262, 1985; Tsutomu Nakamura et al., the same publication, 263-268, 1985; Atsuhiko Tada et al., the same publication, 269-273, 1985; Yasuhiro Oribe et al., "Prostaglandins--Advances in Clinical Applications III," Gendai Iryosha, 145-148, 1985; Hisaji Kamoi et al., the same publication, 149-154, 1985; Hiroyasu Dohgen et al., the same publication, 155-160, 1985; Kazuaki Orita et al., the same publication, 161-166, 1985; Kiyoshi Hashizume et al., the same publication, 167-169, 1985; and literature citing these reports).
In these reports, prostaglandins E.sub.1 are used all as intravenous drips, and nothing has been reported as to a successful therapy with oral administration.
We have conducted intensive research on prostaglandins E.sub.1 which are effective on diabetic neuropathy when administered orally and consequently found that the 7-thiaprostaglandins E.sub.1 represented by the following formula (I) have the desired activity.